About 10-11% (w/w) glycerol is generated as a main by-product of the biodiesel and oleochemical industries. It is estimated that the world biodiesel market will reach 37 billion gallons by 2016 [Yang F, Hanna M A, Sun R. Biotechnology for Biofuels, 2012. 5(1): p. 13], leading to approximately 4 billion gallons of crude glycerol production [Hiremath A, Kannabiran M, Rangaswamy V. New Biotechnology, 2011. 28(1): p. 19-23]. According to estimates, about 2.8 million tonnes of crude glycerol is also produced in Alberta annually. This crude glycerol is expensive to purify and becomes economically unviable to be used in food, pharmaceutical, or cosmetics industries, where pure glycerol is needed. In recent years, with a rapid expansion in biodiesel production, the biodiesel industry is facing a dilemma of how to meet an ever-growing biofuel demand, and manage excessive crude glycerol so that it does not pose a threat to the environment. Therefore, several approaches to utilize/dispose crude glycerol have been investigated, including compositing [Sadano Y, Toshimitsu R, Kohda J, Nakano Y, Yano T. Journal of Material Cycles and Waste Management, 2010. 12(4): p. 308-313], animal feed [Nitayavardhana S, Khanal S K. Bioresource Technology, 2011. 102(10): p. 5808-5814], combustion [Coronado C R, Carvalho J A, Quispe C A, Sotomonte C R. 63(1): p. 97-104], thermochemical [Luo X, Hu S, Zhang X, Li Y. Bioresource Technology, 2013. 139: p. 323-329; Maglinao R L, He B B. Industrial & Engineering Chemistry Research, 2011. 50(10): p. 6028-6033], and biological/microbial conversions [Yazdani S S, Gonzalez R. Current Opinion in Biotechnology, 2007. 18(3): p. 213-219; Xu J, Zhao X, Wang W, Du W, Liu D. Biochemical Engineering Journal, 2012. 65: p. 30-36]. Nevertheless, due to the high amount of impurities, direct utilization of the glycerol is not a viable option and a majority of current conversion approaches lead to either low conversion yields, high amount of co-products during conversion, and high energy consumption, which hampers the large scale viability of such processes. Therefore, the selective conversion of this bio-resource into high value products remains a challenge, and the development of new rapid, efficient and economically viable methodologies is desirable.
Therefore, the transformation of glycerol into valuable compounds has been investigated. Glycerol has been used in the production of hydrogen [Buffoni I N, Pompeo F, Santori G F, Nichio N N. Catalysis Communications, 2009. 10(13): p. 1656-1660; Sabourin-Provost G, Hallenbeck P C. Bioresource Technology, 2009. 100(14): p. 3513-3517], dihydroxyacetone [Painter R M, Pearson D M, Waymouth R M. Angewandte Chemie International Edition, 2010. 49(49): p. 9456-9459], propanediols [Gandarias I, Arias P, Requies J, Güemez M, Fierro J. Applied Catalysis B: Environmental, 2010. 97(1): p. 248-256; Guo L, Zhou J, Mao J, Guo X, Zhang S. Applied Catalysis A: General, 2009. 367(1): p. 93-98], acrolein [Ning L, Ding Y, Chen W, et al. Chinese Journal of Catalysis, 2008. 29(3): p. 212-214; Ulgen A, Hoelderich W F. Applied Catalysis A: General, 2011. 400(1-2): p. 34-38; Alhanash A, Kozhevnikova E F, Kozhevnikov I V. Applied Catalysis A: General, 2010. 378(1): p. 11-18], glycerides [Xu J, Zhao X, Wang W, Du W, Liu D. Biochemical Engineering Journal, 2012. 65: p. 30-36], epichlorohydrin [Dibenedetto A, Angelini A, Aresta M, Ethiraj J, Fragale C, Nocito F. Tetrahedron, 2011. 67(6): p. 1308-1313; Santacesaria E, Tesser R, Di Serio M, Casale L, Verde D. Industrial & Engineering Chemistry Research, 2009. 49(3): p. 964-970.], allyl alcohol [Kamm O, Marvel C. Org. Syn, 1921. 1: p. 15-17; Arceo E, Marsden P, Bergman R G, Ellman J A. Chemical Communications, 2009. (23): p. 3357-3359], acrylic acid [Li X, Zhang Y. ACS Catalysis, 2016. 1(6): p. 143-150; Omata K, Matsumoto K, Murayama T, Ueda W. Catalysis Today, 2016. 259, Part 1: p. 205-212.; Liu L, Wang B, Du Y, Zhong Z, Borgna A. Applied Catalysis B: Environmental, 2015. 174-175: p. 1-12; Possato L G, Cassinelli W H, Garetto T, Pulcinelli S H, Santilli C V, Martins L. Applied Catalysis A: General, 2015. 492: p. 243-251; Shen L, Yin H, Wang A, Lu X, Zhang C. Chemical Engineering Journal, 2014. 244: p. 168-177], lactic acid [Yin H, Zhang C, Yin H, Gao D, Shen L, Wang A. Chemical Engineering Journal, 2016. 288: p. 332-343; Ftouni J, Villandier N, Auneau F, Besson M, Djakovitch L, Pinel C. Catalysis Today, 2015. 257, Part 2: p. 267-273], acrylonitrile [Calvino-Casilda V, Guerrero-Pérez M O, Banares M A. Applied Catalysis B: Environmental, 2010. 95(3-4): p. 192-196], and glycerol carbonate [Dibenedetto A, Angelini A, Aresta M, Ethiraj J, Fragale C, Nocito F. Tetrahedron, 2011. 67(6): p. 1308-1313]. The transformation of glycerol requires in general use of solid catalysts including heteropolyacids [Martinuzzi I, Azizi Y, Zahraa O, Leclerc J. Chemical Engineering Science, 2015. 134: p. 663-670; Martin A, Armbruster U, Atia H. European Journal of Lipid Science and Technology, 2012. 114(1): p. 10-23; Erfle S, Armbruster U, Bentrup U, Martin A, Bruckner A. Applied Catalysis A: General, 2011. 391(1-2): p. 102-109], metal oxides [Braga T P, Essayem N, Valentini A. RSC Advances, 2015. 5(113): p. 93394-93402; Chai S, Tao L, Yan B, Vedrine J C, Xu B. RSC Advances, 2014. 4(9): p. 4619-4630] and zeolites [Possato L G, Cassinelli W H, Garetto T, Pulcinelli S H, Santilli C V, Martins L. Applied Catalysis A: General, 2015. 492: p. 243-251; dos Santos M B, Andrade H M C, Mascarenhas A J S. Microporous and Mesoporous Materials, 2016. 223: p. 105-113; Näfe G, Lopez-Martinez M-, Dyballa M, et al. Journal of Catalysis, 2015. 329: p. 413-424; Carrico C S, Cruz F T, dos Santos M B, et al. Journal of Catalysis, 2016. 334: p. 34-41] at high temperature. Coke deposition [Cheng C K, Foo S Y, Adesina A A. Catalysis Today, 2011. 164(1): p. 268-274] is reported as a cause for catalyst deactivation and low selectivity and conversion. Allyl alcohol (AA) is an important building block for the production of glycidyl ethers [LIU H, ZHANG Z, ZOU J. Industrial Catalysis, 2003. 12: p. 006], esters [Mitsunobu O, Yamada M. Bulletin of the Chemical Society of Japan, 1967. 40(10): p. 2380-2382], amines [Kinoshita H, Shinokubo H, Oshima K. Organic Letters, 2004. 6(22): p. 4085-4088], poly (allyl alcohol) [Volodina V, Tarasov A, Spasskii S. Russian Chemical Reviews, 1970. 39(2): p. 140; Laible R. Chemical Reviews, 1958. 58(5): p. 807-843], and a variety of polymerizable esters like diallyl phthalate [Guo S. In: ACS Publications; 2000].
Canada has over 90% of the total known volumes of oil sands reserves[52] and the Athabasca oil sands deposit is the largest petroleum reserve in the world. Due to exhausting conventional oil resources, bitumen production from oil sands is gaining more attention for the production of synthetic crude oil from tar sands (bitumen). The increasing footprint of fluid fine tailings produced during bitumen extraction from oil sands ores is one of the major environmental concerns that Alberta is facing in the wake of oil sands development. In tailings ponds, coarse solids settle quickly as sand beach while fine particles settle at extremely slow rate. After an extended period of settling, a stable suspension containing about 30 wt % solids is formed that is known as Mature Fine Tailings (MFT). Further densification of dispersed clay particles in fine tailings could take decades, if not centuries, leading to continuous accumulation of MFT at alarming rate.
Various physical, chemical and biological means have been utilized and studied for effective consolidation to reclaim the MFT [X. Li, Y. Feng, J. J. Slaski, M. Fung, Journal of Canadian Petroleum Technology 2003, 42, 47-50; P. Mpofu, J. Addai-Mensah, J. Ralston, Minerals Engineering 2004, 17, 411-423; S. Proskin, D. Sego, M. Alostaz, Cold Regions Science and Technology 2010, 63, 110-120; A. Sworska, J. S. Laskowski, G. Cymerman, International Journal of Mineral Processing 2000, 60, 143-152; X. W. Wang, X. Feng, Z. Xu, J. H. Masliyah, Canadian Journal of Chemical Engineering 2010, 88, 403-410]. Nevertheless these technologies are unsuitable economically and environmentally. The use of gypsum by oil sand industries to enhance the rate of densification results in the constant build-up of calcium and sulfate ions in the recycled water impeding the effectiveness of bitumen extraction[E. Redfield, C. Croser, J. J. Zwiazek, M. D. MacKinnon, C. Qualizza, Journal of Environmental Quality 2003, 32, 1008-1014]. Anionic polymers (polyacrylamides and their derivatives) with high molecular weight have also been used commercially as an organic flocculants to treat fine tailings, providing an enhanced rate of consolidation. However, this require a high dosage of polymer which results in the detachment of clay particles instead of flocks to be settled because of their loose interaction in between clay particles and polymer[J. G. Matthews, W. H. Shaw, M. D. MacKinnon, R. G. Cuddy, International Journal of Surface Mining, Reclamation and Environment 2002, 16, 24-39]. In addition, the fate of these synthetic flocculants is not well known considering some initial reports on degradation of PAM to acrylamide monomer which is a known neurotoxin and potentially human carcinogen.